Two-dimensional (2D) ferroelectric materials demonstrate promising applications in nanoelectronics owing to their ultrathin thickness and spontaneous polarization. However, as the thickness decreases, ferroelectricity is often suppressed by depolarization effects, making 2D ferroelectric materials extremely scarce. Here, we report the intrinsic out-of-plane (OOP) ferroelectricity in 2D Bi₂SiO₅ (BSO) nanosheets. 2D BSO nanosheets were synthesized through a chemical vapor deposition (CVD) process, and their non-centrosymmetric structure was confirmed through second-harmonic generation (SHG) response. Switchable polarization and ferroelectric hysteresis loops in BSO nanosheets are revealed by piezo-response force microscopy (PFM) measurements. The ferroelectric switching behavior is further validated in a device made of a BSO nanosheet. The ferroelectricity in 2D BSO significantly expands the family of 2D ferroelectric materials and paves the way for their integration into nonvolatile memory devices.

High-quality silver nanowires (Ag NWs) are essential for the next-generation flexible transparent conductors (TCs). However, current synthesis methods predominantly rely on inefficient empirical trial-and-error approaches, lacking a universal theoretical framework. Here, we employ the results of thermodynamic analysis to precisely control the in-situ formation of ideal Ag nuclei with tailored crystalline phases and exposed surfaces via supersaturation modulation, enabling the efficient synthesis of high-quality Ag NWs. We found that the addition of two-dimensional additives, such as graphitic carbon nitride (g-C₃N₄), MoS₂, WS₂, Ti₃C₂Tₓ, and graphene oxide (GO), effectively reduces the supersaturation of the crystal growth units, thereby suppressing random nucleation and favoring the formation of high-purity penta-twinned seeds with low-surface-energy (111) facets. Such control over nuclei allows the production of Ag NWs with an average length of 227 μm (aspect ratio > 2200) at a yield of 93%. Consequently, the resulting TCs exhibit a transmittance (T) of 87% at 550 nm and a sheet resistance (R_sq) of 5 Ω/sq, outperforming conventional indium tin oxide (ITO) (typically, T = 84% at 550 nm, R_sq = 10 Ω/sq). Furthermore, when used as transparent heaters, they can reach approximately 118 °C with a rapid heating rate of 10.5 °C/s at a low voltage of just 5 V. This study innovatively proposes a universal mechanism for synthesizing high-quality Ag NWs, facilitating their diverse applications.

Two-dimensional (2D) materials, especially 2D transition metal oxides (TMOs), have garnered significant research attention due to their unique physical and chemical properties and vast potential applications in electronics, optoelectronics, magneto electronics, and energy storage. However, synthesizing 2D TMOs remains a major challenge due to their non-layered lattice structure and the high temperatures required for synthesis. In this study, we report the chemical vapor deposition-based synthesis of high-quality 2D Cr₂O₃ single-crystal nanosheets and investigate their structure and electrical properties. By controlling the growth temperature and carrier gas, we successfully obtained Cr₂O₃ nanosheets with lateral dimensions up to 30 μm and a minimum thickness of 4.7 nm. Optical studies, X-ray diffraction, atomic force microscopy, and transmission electron microscopy confirm that the resulting nanosheets are high-quality single crystals. Electrical measurements reveal that charge transport in Cr₂O₃ devices is influenced by both Schottky emission and Poole–Frenkel emission, leading to a non-equilibrium charge conduction state. This systematic synthesis approach provides a reliable route for fabricating 2D TMO single crystals with controlled thickness and offers a platform for investigating charge transfer at electrode–dielectric interfaces, as well as for the design of novel electronic materials and catalysts.

Phase transition and edge structure reconstruction of two-dimensional (2D) materials are critical for modulating their properties and applications. Here, we employ a hydrogen-assisted annealing method to accomplish the extensive transformation from a 2H MoTe₂ single crystal to Mo₆Te₆ nanowires and quasi-2D Mo₆Te₆ nanoribbons. Introducing hydrogen gas during atmospheric pressure annealing process generates a Te-poor chemical environment, which makes the transformations energetically favorable and is essential for the fast growth of Mo₆Te₆ nanowires. Mo₆Te₆ nanowires nucleate at the exposed edges of 2H MoTe₂ and grow along its [ $11\overline{2}0$], [ $\overline{2}110$], and [ $1\overline{2}10$] crystallographic directions, demonstrating long-range order and forming quais-2D nanoribbons with lengths up to 50 μm. Finally, nanoribbons align in sixfold oriented directions and form an array within 3 mm² area on SiO₂/Si substrate. Mo₆Te₆ nanowires display metallic behavior and have large charge transfer with Rhodamine 6G, making them excellent substrates for surface-enhanced Raman scattering. It shows a low detectable concentration of 10⁻¹³ mol/L for Rhodamine 6G and a Raman enhancement factor of 7 × 10⁸. Our findings provide an economic and efficient synthesis method for producing sixfold-oriented Mo₆Te₆ nanowires and nanoribbons networks, which can serve as platform for exploring low-dimensional physical properties, designing electronic devices, and applications in analytical chemistry.

Large-scale synthesis of high-quality two-dimensional (2D) semiconductors, such as molybdenum disulfide (MoS₂), is a prerequisite for their lab-to-fab transition. It is crucial to systematically explore and understand the influence of key synthetic conditions on the nucleation, uniformity, and quality of MoS₂ wafers. Here, we report the epitaxial growth of high-quality and uniform monolayer MoS₂ films on 2-in c-plane sapphire by chemical vapor deposition (CVD) method under optimized growth conditions (0–1 mg NaCl, adequate S/Mo ratio, and the addition of 0–1 sccm O₂). We systematically explore the influence of critical synthetic conditions on the nucleation, and stitching of MoS₂ domains over the wafer scale, including the dosage of the alkali metal salt NaCl additive, the evaporation temperature of MoO₃, the distance between MoO₃ and the substrate, and the flow rate of O₂. Among them, the dosage of NaCl and the S/Mo ratio have important influences on the quality and film coverage of MoS₂, while the flow rate of O₂ plays a key role in controlling the nucleation density and domain size. We further discovered that a-plane sapphire could easily guide the unidirectional growth of MoS₂ without the need for other specific synthetic conditions compared with c-plane and m-plane sapphire. The field-effect transistors (FETs) fabricated from the full-coverage films show an average and the highest mobilities of 28.5 and around 45 cm²·V⁻¹·s⁻¹, respectively.

Quasi-one-dimensional ZrS₃ nanoflakes attract intense interest attributed to their superior electrical and optical anisotropy, stemming from the low symmetry in the crystal structure. However, the conventional chemical vapor transport method for synthesizing bulk ZrS₃ is limited by morphology and size controllability. It is highly desirable to propose a facile way to precisely synthesize ZrS₃ nanoflakes. In this work, the chemical vapor deposition method is proposed as a feasible way to synthesize ZrS₃ nanoflakes. The effects of various substrates and temperatures on ZrS₃ synthesis have been investigated. For the as-grown ZrS₃, good crystallinity is confirmed with X-ray diffraction and transmission electron microscopy. The structure and interlayer coupling are investigated with Raman scattering spectroscopy. The strong in-plane anisotropy and interlayer coupling of the ZrS₃ nanoflakes are illustrated with angle-resolved Raman spectroscopy and temperature-dependent Raman characterization, respectively. This study demonstrates a feasible way for the synthesis of transition metal trisulfides, which may shed new light on the research of other two-dimensional anisotropic transition metal materials.

Ag nanowire (NW) film is the promising next generation transparent conductor. However, the residual long-chain polyvinylpyrrolidone (PVP, introduced during the synthesis of Ag NWs) layer greatly deteriorates the carrier transport capability of the Ag NW film and as well its long-term stability. Here, we report a one-step I⁻ ion modification strategy to completely replace the PVP layer with an ultrathin, dense layer of I⁻ ions, which not only greatly diminishes the resistance of the Ag NW film itself and that at interface of the Ag NW film and a functional layer (e.g., a current collect electrode) but also effectively isolates the approaching of corrosive species. Consequently, this strategy can simultaneously improve the carrier transport properties of the Ag NW film and its long-term stability, making it an ideal electric component in diverse devices. For example, the transparent heater and pressure sensor made from the I⁻-wrapped Ag NW film, relative to their counterparts made from the PVP-wrapped Ag NW film, deliver much improved heating performance and pressure sensing performance, respectively. These results suggest a facile post treatment approach for thin Ag NW film with improved carrier transport properties and long-term stability, thereby greatly facilitating its downstream applications.

The accomplishment of nanowelding typically requires the input of high energy, possibly causing appreciable damages to the brittle nanomaterial. Herein, we report an external field (EF, i.e., light, direct current (DC), and alternating current (AC))-strengthened Ostwald nanowelding (ONW) strategy to enable low-temperature nanowelding of Au nanoparticles (NPs) with nanoscale spacing in solution and propose an electron localization mechanism to understand it. We reveal that the EF-derived local electrons not only greatly strengthen the dissolution of surface atoms and the reduction of Au³⁺ ions dissolved, but also confine (together with ordered water molecules) the transport of Au³⁺ ions within the nanogap. Consequently, the electrochemical Ostwald ripening (OR) process of the Au NPs is actively strengthened, which, along with the local electron-strengthened surface atom diffusion (as a result of the strong electrostatic repulsion created), enables feasible ONW for solution processing of interdigital electrodes (IDEs) from Au NPs and high-performance transparent conductor (TC) from Ag nanowires (NWs). Our low-temperature nanowelding strategy offers an efficient interconnection technique for the processing of functional nanodevices from individual nanomaterials.

Potassium-ion batteries (PIBs) are of academic and economic significance, but still limited by the lack of highly active electrode materials for de-/intercalation of large-radius K ions. Herein, an interconnected nitrogen/sulfur co-doped carbon nanosheep bundle (N/S-CSB) was proposed as the potassium ions storage material. The rich co-doping of nitrogen/sulfur of N/S-CNB with three-dimensional hierarchical bundled array structure yields distensible interlayer spaces to buffer the volume expansion during K⁺ insertion/extraction, offers more electrochemical active sites to obtain a high specific capacity, and provides efficient channels for fast ion/electron transports. Therefore, the N/S-CSB anode achieved high reversible specific capacity of 365 mAh/g obtained at 50 mA/g after 200 cycles with a coulombic efficiency (CE) close to 100%, high rate performance and long cycle stability. Moreover, the in-situ Raman spectra indicated outstanding reaction kinetics of as-prepared N/S-CSB anode.